Children with cerebral palsy (CP), a brain injury that affects motor function, can develop a number of musculoskeletal problems relating to altered growth - deformities of the bone, joint dislocations, and tight tendons and muscles - as well as increased muscle tone caused by “misfiring” circuits in the brain. Manifestations of cerebral palsy can vary considerably, and orthopedists who treat these patients can face a complex array of conditions.
The major goals in caring for children with cerebral palsy are to optimize their function and prevent deformities. For children who are able to walk, maintaining and optimizing that ability, and the independence it affords, is a primary goal. Treatment goals for children with cerebral palsy who are not able to walk focus on helping the child maintain comfortable, balanced, and level seating in a wheelchair. This helps the child remain upright in order to observe their surroundings, communicate with the world around them, and remain mobile.
Birth to Five Years
During the early years, from birth to about five years of age, orthopedic issues are usually addressed without surgery, according to David M. Scher, MD, an associate attending orthopedic surgeon at Hospital for Special Surgery. “These measures include bracing and spasticity treatments, which can include injections of botulinum toxin (Botox®) to relax overly tight muscles.”
When young children with spasticity are learning to walk, their muscles become tight and their legs are unable to move into the right position at the right time. One of the most effective ways to decrease spasticity is with the use of Botox, which can block some of the activity at the neuromuscular junction to “turn off ” some of the signal moving from nerve to muscle. Although Botox injections can be very effective, these effects are temporary, and repeat injections may be necessary. Pediatric neurologists and neurosurgeons use other pharmacologic and surgical techniques to effectively manage spasticity.
Another commonly used and effective technique for managing spasticity is brace (orthotic) treatment. An appropriately prescribed orthosis can counteract the spastic tone in the calf muscles that causes the foot to point down. Other techniques such as nerve surgery (rhizotomy) and direct delivery of medication to the central nervous system (intrathecal Baclofen) will also manage muscle spasticity.
6 to 10 Years
During the period between 6 and 10 years, ambulatory children become candidates for orthopedic surgery to improve limb alignment. “We try to address all deformities at once,” says Dr. Scher, referring to a process called a single-event, multi-level surgery (SEMLS). Such operations can incorporate numerous procedures, with symmetric surgeries on both sides, involving hips, knees, ankles, and feet.
This approach offers the advantage of a single surgery and rehabilitation period. In addition, Dr. Scher points out that SEMLS provides the best opportunity for achieving optimal alignment. “When alignment is addressed in separate surgeries, an untreated problem above or below the specific area being corrected may jeopardize the success of surgery.”
Among those procedures that may be part of the SEMLS are:
- Tendon transfers: Owing to their underlying disorder, many children with cerebral palsy have one or more tendons that pull too hard in one direction, resulting in a deformity. An example of this is a turned-in foot caused by over-pulling of the tibialis anterior or tibialis posterior tendon. To address the problem, the surgeon transfers half the tendon to the other side, where it acts as a yoke to balance the foot.
Another frequently performed tendon transfer is that of the rectus femoris, which is located around the knee. In such cases, one of the thigh muscles is spastic (overly tight). Because it “fires” at the wrong time, it impedes bending of the knee in the proper manner while the child is walking. By transferring - or moving - this tendon, this procedure can improve how the child walks.
- Muscle and tendon lengthening procedures: Tendon lengthenings have always been a mainstay of the treatment of children with cerebral palsy; however, recent research has shown that, despite short-term improvements in walking, they can sometimes result in weakness in the long-term.
In the past, surgeons would commonly lengthen the Achilles tendon if a child’s ankle was tight and they were walking on their toes. However, today we are much more likely to lengthen muscles in the calf rather then the Achilles tendon. This minimizes the weakness that results and lessens the risk of “over-lengthening” or doing too much. A similar approach is taken to muscle behind the knee (the hamstrings) and in front of the hip (the psoas muscle).
- Osteotomies to correct bone deformities in the hip, knee, and ankle: These deformities may disturb the patient’s gait and, in the case of the hip joint, result in hip dislocation.
Osteotomies involve cutting and reshaping of the bones to restore a more normal alignment. One of the most common sites these surgeries are performed is the femur, or hip bone. The femur often must be bent down into the socket and untwisted, commonly referred to as a varus rotational osteotomy (VRO) or derotational osteotomy (DRO).
- Foot re-alignment surgery: A wide variety of surgeries can be performed in the foot to correct deformities that often develop in children with CP. One of the most common is a flat foot, also known as a planovalgus foot. This can impede a child’s ability to generate power when they are pushing off with the foot during while walking.
Surgeries to cut and reposition the heel bone, called calcaneal osteotomies or calcaneal lengthening osteotomies, along with other surgeries of the foot bones, called tarsal and metatarsal bones, can put the foot in better position for walking. When children with CP get bunions (hallux valgus), the bunion is usually corrected by straightening the bones and making the joint solid, called a fusion or arthodesis.
“Surgeries can be especially effective in maximizing the child’s abilities,” says Dr. Scher. “ In some cases, not only is walking ability enhanced, but the child is eventually able to run, jump, and play as any other child does, with minimal impairment.”
Orthopedic surgeons try to achieve these results before the adolescent growth spurt, which begins around the time of puberty. The hope is that once alignment is achieved, growth proceeds normally and the child can be expected to remain upright and pain-free.
However, Dr. Scher says, some problems such as tendon contractions can recur, especially if surgery is necessary at an early age in a child with highly increased muscle tone.
Moreover, children with hip dislocations at an early age are at increased risk of recurrence. “Once the joint is dislocated, however, we have to correct it,” Dr. Scher says. Left untreated, the deformity will increase and arthritis will develop.
Prior to surgical intervention at HSS, some ambulatory children with cerebral palsy may benefit from a gait analysis in the Hospital’s Motion Analysis Laboratory. This sophisticated tool captures digital recordings of joint movement and electrical signals from the muscles that yield information not visible to the naked eye.
“This technology allows us to simultaneously analyze movement of the trunk, pelvis, hips, knees, ankles, and feet in three planes; how and when muscles are firing at different stages of the gait; and the forces on the joints during walking,” Dr. Scher explains. “By performing the studies before and after surgery, we’re able to refine our treatment approach and measure the success of surgical interventions.” The Leon Root, M.D. Motion Analysis Laboratory at HSS is the only clinical facility of its kind in the metropolitan New York area.
Non-ambulatory children with cerebral palsy are at increased risk for hip dislocation, compared with their ambulatory counterparts, and often require more complex surgery to correct the problem, owing to a greater degree of deformity in the bones. In these cases, the orthopedic surgeon may need to perform an osteotomy of the pelvis (just above the hip socket) in order to re-shape a socket that has become shallow. This is typically done in addition to the surgery on the femur, or VRO, done in ambulatory children.
Lengthening of tendons is often necessary, both to help keep the hips in the sockets and to promote standing and walking programs in supervised therapy sessions. Other surgeries similar to those done in ambulatory children are sometimes necessary to help children remain seated in the most optimal position.
Extensive research into the care of children with cerebral palsy, done at HSS and at other centers around the world, has helped us dramatically improve the quality of life of children with CP. With tools such as motion analysis at their disposal and a better understanding of how to achieve optimal mechanical function, orthopedists at HSS are able to offer many patients with cerebral palsy significant improvement in function.
For more information on the treatment of cerebral palsy at HSS, please visit the Physician Referral Service or call 1.877.606.1555.
Summary Prepared by Nancy Novick